Corrugated board



Nov. 24, 1970 Original Filed July 28, 1965 K. WANDEL CORRUGATED BOARD 3Sheets-Sheet 1 INVENTOR.

' KURT WANDEL BY z,

ATTORNEYS N5 24; 1970 'K. WAND EL I 3,542,636

- CORRUGATED BOARD or mai' Filed Jdly 28. 1965 :5 Sheets-Sheet? v INVENTKURT WAN $49K d Mi A. 7 ATTORNEYS K. WANDEL CORRUGATED BOARD.

' Nov. 24, 1970 3 Sheets-Sheet 5 Original Filed July 28. 1965 INVENTOR.KURT WANDEL BY 3% z ATTORNEYS United States Patent US. Cl. 161-114 5Claims ABSTRACT OF THE DISCLOSURE A corrugated member comprising aplurality of strips of elongated material folded into trough-shapeslongitudinally thereof and secured together with the troughshaped sidesof alternate strips facing in opposite directions.

This is a divisional application of my copending application Ser. No.475,402, filed July 28, 1965, now Pat. No. 3,449,157.

This invention relates to an improved corrugated structure and inparticular to a continuously formed longitudinally corrugated boardpossessing a high degree of strength not present with conventionaltransversely corrugated board and to a composite corrugated membercomprised of a longitudinally and transversely corrugated boardconnected together in such a way whereby the corrugations of theindividual boards extend crosswise of eachother to produce a member thatis resistant to both crushing and bending.

Corrugated boards are usually produced in a continuous fashion from anelongated web of paperboard with the corrugations extending transverselyof the web. For producing these corrugations, the web is fed in adirection along its length and through a pair of parallel rolls havingflutes on their outer surfaces extending along the axes of the rolls.The flutes of the rolls cooperate in a mating relationship to bend theweb into a fluted pattern extending across its width. Facing material isthen glued to one or both sides of the fluted or corrugated web toproduce the final product. During the corrugating of the web, it isapparent that its overall effective length is shortened due to theproduction of flutes. This, however, presents no problems in thecontinuous operation of the corrugating machinery since the corrugationsextend transversely of the length of the web and the decrease in overalllength is compensated for by simply controlling the speed of movement ofthe web on either side of the corrugating rolls.

Attempts have been made in the past to produce an elongated corrugatedboard from a single web of material with the corrugations extendinglongitudinally thereof; however, the production of such boards presentscertain difficulties due to the necessary contraction in the overallwidth of the web that must be effected in producing the corrugations.The machinery used in producing such boards must be constructed topermit the web to move transversely of its forward path of movement andsuch transverse movement is complicated by the fact that eachlongitudinally extending segment of the web that will form the sides ofthe longitudinally extending flutes must move in opposite directions toproduce such flutes.

Due to the difficulties encountered in producing longitudinallycorrugated boards such as described above, industry has generally cometo prefer and accept corrugated boards formed from a continuous web ofmaterial which has been corrugated transversely of its length. Theseboards possess good resistance against crushing but because thecorrugations of these boards extend in only one direction, they giveonly one-way strength or stiffness; that is, they resist bending alonglines extending ice at right angles to the corrugations but are readilybendable in a direction along the corrugations.

Attempts in the past have been made to unite separate corrugated boardswith the corrugations extending crosswise of each other; however, boardsof this construction double the overall thickness of the compositeboard. Also, limitations are imposed on the overall length of suchboards where they are formed from transversely corrugated webs in thesense that the length of the composite board is limited by the width ofthe board that is to be used as the longitudinally corrugated member.Also, in order to construct such composite structures from individualboards previously produced by transversely corrugating a Web material,the individual boards must be cut to the appropriate size beforeassembly to each other. This can involve additional time and requirethat the assembly operation be carried out in an intermittent fashion orat best with complicated machinery operating in a continuous fashion. Itis apparent that such manufacturing methods can easily add to theoverall expense of such composite constructions.

In accordance with the teachings of the present invention, a continuouslength of longitudinally corrugated board is produced by employing twoweb materials, each of which is slit into individual strips,subsequently folded into a trough shape, and adhesively attached to eachother along their longitudinal edges in a fluted or corrugatedrelationship. By employing two webs as opposed to a single web and bydividing each of these webs into individual strips, the problems thatmight otherwise be encountered in compensating for the necessarytransverse movement of the web are avoided; and by simply olfsetting oneof the webs laterally of the other, each of the individual strips of oneof the webs will automatically be aligned with the strips of the otherweb as they are brought together in their longitudinally foldedcondition. As a result of using a pair of slit webs, the entirelongitudinal corrugating operation may be effected in a continuousfashion and the board which is produced fed directly into alignment witha transversely corrugated board formed by conventional methods.Attachment of these two boards together will then produce a compositeboard with the corrugations extending at right angles to each other.

For purposes of structurally reinforcing the composite structure, thetransversely corrugated board is provided with longitudinally extendingrows of apertures in the raised flutes with each of the rows spacedapart by a distance equal to the spacing of the flutes of thelongitudinally corrugated board. When the two boards are broughttogether, the flutes of the longitudinally corrugated board are seatedin mating relationship within the apertures of the transverselycorrugated board and adhesively united in this relationship.

The adhesive used in attaching the various parts of boards together isadvantageously a hot melt adhesive which is rendered tacky upon beingheated. This adhesive is impregnated into the web materials and adds tothe integral strength of the final structure. In addition, the strengthof the longitudinally corrugated member is increased by the doublethickness produced by the overlapping of the individual strips; andsince the longitudinally corrugated member is formed from individualstrips that require only one folding, it is not necessary toprecondition the strips to render them soft and pliable before suchfolding is effected. With a single web folded in a reverse pattern toform the corrugations, it is usually necessary to presaturate the webmaterial with water or steam so that the corrugations will set upon thedrying of the corrugated board. The addition of this moisture to thematerial is in some situations undesirable in that it tends to weakenthe strength of the resulting board.

The composite board produced in accordance with the teachings of thepresent invention possesses certain advantageous characteristics thatrender it particularly useful in producing many types of shippingcontainers. The board is not only lightweight; but due to thecross-corrugations it is extremely rigid and will resist both crushingand bending in all directions. These features also render the boarduniquely suited for use as building panels in much the same manner asplywood sheets are now used today. Also, due to the voids formed by thecorrugations, these boards possess desirable soundproof characteristics;and these voids may be filled with suitable material to render thecomposite structure fire resistant and at the same time give it goodinsulating qualities.

A more complete understanding of the invention will be obtained from areading of the following detailed description with reference being madeto the accompanying drawings of which:

FIG. 1 is a schematic side elevation of the portion of the apparatus forforming the longitudinally corrugated member;

FIG. 2 is a schematic side elevation of the'portion of the apparatus foruniting the transversely corrugated member to the longitudinallycorrugated member;

FIG. 3 is a partial side elevational view of the scoring rolls shown inFIG. 1;

FIG. 4 is a partial side elevational view of a modified embodiment ofthe scoring rolls;

FIG. 5 is a partial side elevational view of the slitting rolls shown inFIG. 1;

FIG. 6 is a partial cross-sectional view of the folding rolls takenalong line 66 of FIG. 1;

FIG. 7 is a partial cross-sectional view of the cutting rolls takenalong line 7-7 of FIG. 2;

FIG. 8 is a perspective view partially broken away of a portion of acomposite corrugated member formed by the apparatus of FIGS. 1 and 2;

FIG. 9 is a perspective view of a modified embodiment of a compositecorrugated member;

FIG. 10 is a perspective view partially broken away of another modifiedembodiment of the composite corrugated member; and

FIG. 11 is a perspective view of the board formed by the apparatus ofFIG. 1.

As shown in FIG. 1, the portion of the apparatus for producing thelongitudinally corrugated board comprises upper and lower sections. Eachof these sections include substantially identical parts and accordingly,in describing this portion of the apparatus, the reference numbers usedto designate like parts will be the same with those of the lower sectionfollowed by the character prime Referring to FIG. 1, two rolls of webmaterials 1 and 1', such as paperboard, are shown as being rotatablypositioned on suitable supports. The webs drawn from these supplies areled through various operating sections of the apparatus, the first ofwhich is the scoring mechanism 2 and 2'. With reference to the uppersection of the apparatus, the scoring mechanism consists of a pair ofcooperating rolls 3, 4 disposed on opposite sides of the web 1. Thesescoring rolls may be of any conventional construction and as representedin FIG. 3, the lower roll 4 over which the web is entrained has a smoothcylindrical surface while the other cooperating roll 3 is provided witha plurality of spaced circumferentially extending scoring ribs 5 forproducing longitudinally extending fold lines on the Web 1. The scoringmechanism shown in FIG. 3 produces a plurality of laterally spacedsingle fold lines; however, as an alternative to this, the scoring ribsmay be constructed in the shape shown in FIG. 4 where a plurality ofraised closely aligned ribs 5 are provided so as to produce a pluralityof closely aligned fold lines at spaced intervals across the web. Byhaving a plurality of closely aligned folding lines, the folding of theweb along these lines will produce a more pronounced curedconfiguration.

After the web 1 passes through the scoring rolls, it is fed to anadhesive applicator 6. This applicator is comprised of an applicatorroll 7 partially disposed within an adhesive trough 8 and a cooperatingback-up roll 9. As the web moves between these rolls, the adhesive roll7 is caused to rotate and transfer adhesive from the trough 8 to thebottom side of the web 1. The adhesive employed for this purpose is ahot melt adhesive which may be comprised of hot asphalt or a suitablesynthetic resin such as Tufiin manufactured by The Atlantic RefiningCompany. The adhesive becomes tacky upon heating; and in applying theadhesive to the web material in either a continuous or stripped pattern,pressure is exerted by the rolls 7 and 9 to the effect an impregnationof the adhesive into the web material and a coating of one side thereof.In the past, glue made from starch or silicate of soda has been used asthe adhesive in making corrugated paperboard. Such an adhesive containsa considerable amount of water, and the addition of this water to theweb material tends to weaken it. With a hot melt adhesive such as hotasphalt, the stiffness of the corrugated web is increased rather thanweakened.

Once the adhesive has been applied to the web, the coated material isfed through a slitting mechanism generally designated at 10. Thisslitting mechanism is comprised of a pair of cooperating rolls 11 and 12for slitting the web longitudinally midway between the fold lines. Asshown in FIG. 5, the roll 11 is provided with a plurality of spacedblade-like surfaces 13 cooperating with grooves 14 formed in the roll12. The strips 15 formed by this slitting mechanism have theirlongitudinal edges closely aligned with respect to each other as theypass toward the next operating station in the apparatus where the twowebs, both of which are now slit into strips, are joined together in acorrugated pattern.

For producing the composite corrugated web, a corrugating mechanismgenerally designated at 16 is provided. This mechanism includes a pairof cooperating rolls I17 and 18 disposed on opposite sides of the webmaterials 1 and 1'. These two rolls are identical in construction and asshown in FIG. 6 are provided with circumferentially extending foldingribs 19, 20, respectively. Between each of these folding ribs, the rolls17, 18 are provided with grooves 21, 22. These grooves extend radiallyinwardly of the folding surface of the ribs to provide a free space intowhich the folded edge of the strips may extend without contacting therolls. The first strips 15 formed from the first web material 1 arepassed between the rolls 17, 18 and about the folding ribs 19 of theroll 17. These folding ribs are aligned with respect to the spaced foldlines in the first web so that the fold line of each strip will contactone of the ribs along its outermost edge 19'. As the strips are drawnunder the roll -17, they will be folded about the folding ribs andautomatically spaced laterally of each other. The second strips 15'formed from the second web 1' are passed about the cooperating roll '18in the same manner as the first strips are led about the roll 17. At thepoint where the second strips are fed into the corrugating mechanism,they are offset laterally of the first strips so as to be in properorientation with the folding ribs 20. This is effected by mounting thesupply roll for the first web material and its associated scoring,adhesive, and slitting mechanism at a position offset laterally fromthat used with the first web material. As the first strips and secondstrips are fed between the rolls 17 and 18, the sides to which theadhesive has been applied will face each other and be in pressureengagement therewith. The rolls 17 and 18 are heated by suitable meansrepresented diagrammatically at 23, 24 so as to assure that the hot meltadhesive is tacky at the time when the strips are brought together toeffect a uniting thereof. a

As shown in FIG. 6, the first strips span the lateral spaces between thesecond strips and the exposed portions 25 of the sides to which theadhesive has been applied are received within the grooves 22 out ofcontact with the roll 18. Likewise, the second strips span the spacingbetween the first strips and are similarly oriented with respect to thechannels of the roll 17.

Disposed beyond the rolls 17 and 18 is a feeding mechanism generallydesignated at 26. This mechanism comprises cooperating feed rolls 27, 28disposed on opposite sides of the composite corrugated web as it exitsfrom the rolls 17 and 18. These rolls provide the pulling power fordrawing the web through the various mechanisms by which the strips areformed, folded, and united. As shown in FIG. 2, the corrugated compositeweb exiting from the corrugating mechanism is provided with a linerboard or facing web 29 on its underside. This facing web is fed betweencooperating rolls of an adhesive applicator 30 generally similar toapplicators '6 and 6' and then about the feed roll 28 into engagementwith the lower side of the composite corrugated web. The roll 28 isheated by the means shown diagrammatically at 31 and presses the facingweb 29 into pressure engagement with the exposed surfaces 25 of thestrips 15. It is to be noted that these surfaces 25 have alreadyreceived a coating of adhesive and are thus ready to receive the facingweb 29. The application of additional adhesive to the facing web 29assures a proper uniting of the web 29 to the corrugated web and inaddition, adds stiifness to the web 29 upon setting.

As the longitudinal member exits from the machine of FIG. 1, it may alsobe provided with a facing web 29' on its upper face to produce thestructure shown in FIG. ll. This structure possesses a high degree ofstrength not obtainable with a conventional transversely corrugatedmember made of the same weight material. This is so, due to the factthat the strips forming the corrugations are overlapped and because thestructure has been formed without the usual saturation of the materialthat is required with conventional transversely corrugated boards inorder to permit the material to set once it has been bent into thecorrugated pattern.

Disposed on the upper side of the composite corrugated web is a lengthof transversely corrugated board 32. This board is comprised of a facingweb 33 to which is attached a transversely corrugated web 34. The board,as it is led toward the longitudinally corrugated board, is first passedthrough a cutting mechanism designated at 35. As shown in FIG. 7, thiscutting mechanism is comprised of a pair of rolls 36, 37 disposed onopposite sides of the board 32. The roll 36 is constructed with aplurality of grinding ribs 38 spaced laterally across the roll 36. Theroll 36 is driven at a high speed relative to the movement of the board32 to form the longitudinally extending apertures 39 in the transversecorrugations. These apertures cut the raised flutes 40 of thecorrugations along laterally spaced rows. As shown in FIG. 8, thespacing between these rows of apertures corresponds to the spacing ofthe raised flutes on the longitudinally corrugated board exiting fromthe corrugating mechanism 16. The transversely corrugated board ispassed through an adhesive applicator 41 and then under the feed roll 27into overlying engagement with the longitudinally corrugated member withthe exposed flutes of the longitudinally corrugated member seatedagainst the bottom of the apertures formed in the transverselycorrugated member.

The corrugated composite board formed by the apparatus just described isshown in FIG. 8. It is to be noted that the overall thickness of thecomposite structure is not much greater than the individual thickness ofeither of the boards and that the two boards are securely lockedtogether with a type of tongue and groove connection.

With the corrugations of the individual boards extending crosswise ofeach other, resistance against bending in either direction is obtained.This makes the composite structure well suited for use as buildingpanels.

Instead of using an interlocking connection as shown in FIG. 8, thecomposite board may be formed in the manner shown in FIG. 9 where bothof the corrugated members are provided with a facing web 42 on the sidesabutting each other. Alternatively, these interior facing webs may beomitted altogether and the two boards secured together with the exposedflutes of one of the boards lying directly upon and across the exposedflutes of the other board.

-It is to be noted that in FIGS. 8 and 9 the corrugations within theborders of the composite structure form voids. These voids give thestructure good acoustical qualities which are particularly desirablewhere they are used as wall or ceiling panels. In addition, these voidspermit the boards to be readily adapted for use as insulating orfireproof panels. More particularly, the voids either all or some ofthem can be filled with an insulating or fire resistant material. Amixture of asbestos fibers and expanded perlite particles not only givesthe board good thermal insulating qualities but also renders it fireresistant. A composite board construction filled in this manner is shownin FIG. 10 where the mixture of asbestos fibers and expanded perliteparticles is shown at 43. The voids may also be filled with othersuitable materials to add insulating or fire resistant qualities. Forexample, asphalt and expanded perlite particles or asbestos fibers maybe used. In addition, vermiculite, a very absorbent material, can beused together with asphalt. Although asphalt is subject to burning, itneeds oxygen in which to burn, and with the voids of the compositestructure completely filled, oxygen is prevented from supportingcombustion of the asphalt. In addition, the exposed facing webs of thecomposite structure may be made of any material which may advantageouslybe fireproof and/or decorative in nature. For example, single or doublewood veneers may be used for building panels.

The above description of my invention is made with reference to thepreferred embodiments; however, it is to be understood that variouschanges thereto may be made without departing from the scope of theinvention as set forth in the following claims.

I claim:

-1. A corrugated member comprising:

(a) a plurality of first strips of elongated material folded into opentrough shapes longitudinally thereof;

(b) a plurality of second strips of elongated material folded intotrough shapes longitudinally thereof with the trough shaped sides ofsaid first facing in a direction opposite and away from the troughshaped sides of the second strips and with the opposite sides of each ofsaid first strips adhesively united in overlapping relationship to theopposite sides of the two adjacent second strips to form a compositelongitudinally corrugated web; and

(c) a separate facing web adhesively attached to at least one side ofsaid composite corrugated web.

2. A composite corrugated member comprising:

(a) a plurality of first strips of elongated material folded into troughshapes longitudinally thereof;

(b) a plurality of second strips of elongated material folded intotrough shapes longitudinally thereof with the trough shaped sides ofsaid first strips facing in a direction opposite and away from thetrough shaped sides of the second strips and with the opposite sides ofeach of said first strips adhesively united in overlapping relationshipto the opposite sides of the two adjacent second strips to form acomposite longitudinally corrugated web;

(c) a separate facing web adhesively attached to at least one side ofsaid composite corrugated web; and

(d) a transversely corrugated elongated member adhesively united alongone side to one side of said longitudinally corrugated member, saidtransversely corrugated member including:

(1) a transversely corrugated web, and (2) a facing web adhesivelyunited to at least one side of said corrugated web.

3. A composite corrugated member according to claim 2 wherein:

(a) the voids within the borders of said composite member formed by thecorrugated webs are filled with a fire resistant material.

4. A composite corrugated member according to claim 3 wherein:

(a) said strips are adhesively united together by a hot melt adhesiveimpregnated into said strips; and

(b) said fire resistant material includes a mixture of asphalt andexpanded perlite particles.

5. A composite corrugated member comprising:

(a) a plurality of first strips of elongated material folded into troughshapes longitudinally thereof;

(b) a plurality of second strips of elongated material folded intotrough shapes longitudinally thereof with the trough shaped sides ofsaid first strips facing in a direction opposite and away from thetrough shaped sides of the second strips and with the opposite sides ofeach of said first strips adhesively united in overlapping relationshipto the opposite sides of the two adjacent second strips to form acomposite longitudinally corrugated web;

(c) a separate facing web adhesively attached to one side of saidcomposite corrugated web; and (d) a transversely corrugated memberadhesively united to said longitudinally corrugated member, saidtransversely corrugated member including: (1) a transversely corrugatedweb, (2) a facing web adhesively united to one side of said web, and (3)a plurality of apertures formed in the exposed fiutes of said corrugatedweb along longitudinally extending rows spaced laterally of each otherwith the apertures of each row receiving one of the exposed flutes ofthe longitudinally corrugated composite web.

References Cited UNiTED STATES PATENTS 1,875,188 8/1932 Williams l611362,122,479 7/1938 London 161-136 2,198,885 4/1940 Price 161l39 FOREIGNPATENTS 677,215 12/ 1929 France. 957,619 8/1949 France. 73,827 9/1960France.

MORRIS SUSSMAN, Primary Examiner US. Cl. X.R.

